ageing

Indicators of human longevity are on an upward trend in five groups of countries around the world, and the gap between women and men is narrowing, according to a study published in PLoS ONE. The gender gap in life expectancy resulting from the harmful effect of men's blue-collar jobs will shrink, but will persist in the future because men have a higher risk of certain diseases, the authors write. The research team, which includes scientists from the universities of Alcalá́, Barcelona, Oxford and London (UK), uses data and projections for 194 countries from 1990 to 2030.

A Danish study involving over half a million individuals aged 50 and above, tracked for an average of nearly nine years, reveals that hearing loss is associated with a higher risk of dementia, particularly among those who do not use hearing aids. According to the authors, whose research is published in JAMA Otolaryngology–Head & Neck Surgery, this suggests that hearing aids may prevent or delay the onset and progression of dementia.

A study of more than 5,000 patients has developed a method to predict the biological age of our organs. They have analysed more than 4,000 proteins present in the blood and used machine learning models adapted to 11 different organs. According to the authors, almost 20 % of the population has accelerated organ ageing, which in many cases is associated with an increased risk of mortality of between 20 and 50 %. The results are published in the journal Nature.

Living as a private renter is associated with faster biological ageing than owning a home, according to a study using a UK database with data available on 1,420 people. The team, whose research is published in the Journal of Epidemiology and Community Health, used DNA methylation data - chemical modifications - to measure people's biological age, and says this correlation is stronger than the association between biological ageing and unemployment, or having been a smoker. Apart from blood samples from the database, the research also used historical data from a national survey.

Klotho is a protein whose concentrations tend to decline with age and which has been linked to ageing processes. Now, researchers have found that administration of the protein improves cognitive function in aged rhesus macaques, including benefits in spatial and working memory. According to the authors, who publish the results in the journal Nature Aging, its use "may be therapeutic in humans".

Taurine is one of the most abundant amino acids in animals. As reported in research published in Science, its loss may contribute to the ageing process. According to the study, reversing age-associated taurine deficiency through supplementation improved life expectancy in worms and rodents, while improving some health parameters in non-human primates, which the authors believe would warrant further human trials to examine its effect on life expectancy and the potential risks involved.

Researchers have shown that hypoxia, or oxygen restriction - equivalent to living at 5,000 metres above sea level - increases life expectancy by up to 50% and decreases neurological decline in laboratory mice. It has already been shown in yeast, worms and flies, but this is the first time it has been demonstrated in mammals. The results are published in the journal PLOS Biology. 

The human population could break longevity records in the next few decades, according to a study based on cohort data from 19 industrialised countries - including Spain - that cover records from as far back as the 19th century. Throughout history, mortality has tended to compress, with occasional episodes of delayed mortality, something the authors say suggests that we are still far from maximum human longevity. The research, published in PLoS ONE, points out that cohorts born from 1900 to 1950 will only be able to break longevity records if policies continue to support the health and well-being of older people, and if the political, environmental and economic environment remains stable.

A study published by the company Rejuvenate Bio claims to have prolonged the life expectancy of healthy older mice, while improving other health parameters. The study used a gene therapy—introducing three genes, known as Yamanaka factors, that are particularly active in embryonic cells. According to the authors, the remaining life expectancy of the mice (whose age was equivalent to about 77 years in humans) was doubled, with a 7% increase in absolute terms. The results have been shared in a pre-print publication and have not yet been peer-reviewed. 

Caloric restriction (substantially reducing food intake in a controlled way) prolongs longevity in many animal species. A new result in mice, published in Science, finds that this effect is greater if the animals only eat during the body's natural active phase.